Several different types of one-piece surgical clips are known for ligating vessels and ducts. One type utilizes a V-shape for pinching the vessel closed between the straight legs of the one-piece clip. A problem with this V-shaped configuration is that as the legs of the clip are brought together, the vessel is commonly pushed either partially or completely out from between the free ends of the legs. In addition, vessels and ducts of the human body are inherently slippery and very elastic, which compounds the problem of open-ended clips being unable to completely ligate or clamp a vessel shut. To combat these problems, physicians typically strip or dissect tissue from a vessel to be ligated for circumferential exposure. Even then, the physician must push the open-ended clip against the vessel and away from his line of sight. Knowing this, physicians typically place additional ligating clips in an effort to ensure that a vessel or duct is completely clamped shut. A problem with this approach is that many needless clips are utilized and that the length of an exposed vessel or duct can be limited for the placement of these additional clips. Another problem is that loose or detached clips must be retrieved, which is time consuming, particularly in an endoscopic procedure. One solution to this problem has been to utilize a modified V-shaped configuration in which a knee-bend is formed in each of the legs. This modified V-shaped configuration allows the bent legs to be closed in a parallel manner. However, vessels still slip or slide out of these modified V-shaped ligating clips during application to a vessel or duct.
Another type of one-piece surgical clip employs a generally U-shaped configuration and also closes in a parallel manner similar to the modified V-shaped clip. However, the position of the kink formed in the U-shaped bend during closure of the clip must be carefully controlled to maintain the relative position of the legs. Otherwise, the U-shaped clip becomes V-shaped with all the aforementioned problems of vessel slippage.
Although the U-shaped clip and the knee bend in each of the legs of the modified V-shaped clip are intended to reduce vessel slippage out the open end, vessels are still very wet and slippery and tend to slide out of these open-ended clips. To further reduce vessel slippage out of the U-shaped and modified V-shaped clips, serrations or indentations have been formed on the inside of the legs for gripping and holding the vessel during closure of the clip. In spite of these multiple improvements to reduce slippage of the vessel out the open end, the vessel is often not completely clamped shut by the clip, thus requiring placement of additional ligating clips.
Another modification to the U-shaped or modified V-shaped one-piece clip is the use of a hook and catch at the ends of the legs. This hook and catch combination provides closure around the entire circumference of the vessel, thus reducing the problem of vessel slippage out the open end of the clip. However, this hook and catch combination often does not close around oversized vessels and is susceptible to reopening due to lateral or up-and-down movement of the clip legs. When the hook and catch disengages, the vessel can slide, once again, out the open end of the clip. In an attempt to correct this disengagement problem, several one-piece hook and catch clips include one or more lateral stops. The lateral stops reduce lateral or up-and-down movement of the hook and catch in opposite directions.
A separate two-piece clip is used to bridge an incision in fascia tissue, but not to ligate a vessel or duct. The fascia clip includes an elongated base and a flexible strap that is passed through separate openings at the opposite ends of the base. The base is sized to bridge over the incision. The strap has a pointed distal end for passage through the opening at one end of the base, through the fascia tissue, and under the incision. An applicator holding the fascia tissue in position directs the distal end of the strap once again through the fascia tissue on the other side of the incision and through the opening at the opposite end of the clip base. An enlarged head at one end of the strap prevents passage through one opening of the strap, while teeth at the other end of the strap engage the opening at the opposite end of the strap. Although suited for bridging an incision in fascia tissue, this two-piece fascia clip is not suitable for duct or vessel ligation due to the construction of the required clip applicator. In addition, this two-piece fascia clip is unsuitable for minimally invasive procedures, which typically utilize a hollow 10 mm access sheath.